U.S. patent number 5,603,611 [Application Number 08/617,291] was granted by the patent office on 1997-02-18 for piston type compressor with simple but vibration-reducing suction reed valve mechanism.
This patent grant is currently assigned to Kabushiki Kaisha Toyoda Jidoshokki Seisakusho. Invention is credited to Noriyuki Shintoku, Tomoji Tarutani.
United States Patent |
5,603,611 |
Tarutani , et al. |
February 18, 1997 |
Piston type compressor with simple but vibration-reducing suction
reed valve mechanism
Abstract
A piston type compressor provided with a suction valve mechanism
which includes a suction valve element having suction reed valves
openably closing suction ports for providing a fluid communication
between a suction chamber for refrigerant gas before compression
and cylinder bores in which pistons reciprocate to compress the
refrigerant gas. The cylinder bores are provided with a first
axially recessed engaging face engaging with frontmost end portions
of the suction reed valves to provide the suction reed valve with a
preliminary step of stopping condition, and a second axially
recessed engaging face portions engaged with an inner portion of
the suction reed valves to provide the suction reed valve with a
final step of stopping condition. The preliminary step of stopping
condition of the suction reed valves ensures suppression of
uncontrolled self-vibration of the suction reed valves, and the
final step of stopping condition of the suction reed valves ensures
a stable and optimum amount of opening of the suction reed
valves.
Inventors: |
Tarutani; Tomoji (Kariya,
JP), Shintoku; Noriyuki (Kariya, JP) |
Assignee: |
Kabushiki Kaisha Toyoda Jidoshokki
Seisakusho (Aichi-ken, JP)
|
Family
ID: |
13214627 |
Appl.
No.: |
08/617,291 |
Filed: |
March 18, 1996 |
Foreign Application Priority Data
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|
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|
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Mar 22, 1995 [JP] |
|
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7-062934 |
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Current U.S.
Class: |
417/269; 417/569;
417/571; 137/856 |
Current CPC
Class: |
F04B
39/1073 (20130101); Y10T 137/7892 (20150401) |
Current International
Class: |
F04B
39/10 (20060101); F04B 001/12 () |
Field of
Search: |
;417/269,569,571
;137/856 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gluck; Richard E.
Attorney, Agent or Firm: Burgess, Ryan and Wayne
Claims
What we claim:
1. A piston type refrigerant compressor comprising:
a cylinder block provided with a plurality of cylinder bores
circumferentially arranged around a central axis thereof, said
cylinder bores receiving a plurality of reciprocating pistons;
at least one valve plate adjacent to an axial end of said cylinder
block, and provided with a plurality of pairs of suction and
discharge ports bored therethrough at positions in registration
with said respective cylinder bores;
a suction valve element in contact with one face of said valve
plate, and including a plurality of suction reed valves for
openably closing said suction sports of said valve plate;
a discharge valve element in contact with said other face of said
valve plate for openably closing said discharge ports of said valve
plate;
at least one housing closing said axial end of said cylinder block
via said valve plate, and defining therein a suction chamber for
refrigerant gas before compression and a discharge chamber for said
refrigerant gas after compression;
a suction valve stop means at end portions of said respective
cylinder bores engaged by free ends of said respective suction reed
valves during continuous operation of said suction valve element;
and
said suction valve stop means comprising:
a first predetermined engaging face having a first predetermined
depth with respect to said axial end of said cylinder block and
being engaged by a frontmost portion of said free end of each
suction reed valve to thereby provide each said suction reed valve
with a preliminary step of stopping motion; and,
a second predetermined engaging face having a second predetermined
depth larger than that of said first predetermined engaging face
with respect to said axial end of said cylinder block, said second
predetermined engaging face being engaged with said free end of
each suction reed valve at a portion contiguous to said frontmost
portion thereof to thereby provide said each suction reed valve
with a final step of stopping motion.
2. A piston type compressor according to claim 1, wherein said
first and second predetermined engaging faces of said suction valve
stopping means comprise first and second partial counter-bored
faces formed in said end portions of said respective cylinder
bores, said first and second partial counter-bored faces being
enclosed by a first and second partial cylindrical walls,
respectively.
3. A piston type compressor according to claim 2, wherein said
first and second partial cylindrical walls of the suction valve
stopping means have an equal radius of curvature.
4. A piston type compressor comprising:
a cylinder block provided with front and rear axial ends and a
plurality of cylinder bores circumferentially arranged around a
central axis thereof, said cylinder bores receiving a plurality of
reciprocating double-headed pistons;
a front valve plate adjacent to the front axial end of said
cylinder block, and provided with a plurality of pairs of front
suction and discharge ports bored therethrough at positions in
registration with said respective cylinder bores;
a rear valve plate adjacent to the rear axial end of said cylinder
block, and provided with a plurality of pairs of rear suction and
discharge ports bored therethrough at positions in registration
with said respective cylinder bores;
a front suction valve element in contact with said front valve
plate, and including a plurality of front suction reed valves for
openably closing said front suction ports of said front valve
plate;
a rear suction valve element in contact with said rear valve plate,
and including a plurality of rear suction reed valves for openably
closing said rear suction ports of said rear valve plate;
a front discharge valve element in contact with said front valve
plate for openably closing said discharge ports of said front valve
plate;
a rear discharge valve element in contact with said rear valve
plate for openably closing said discharge ports of said rear valve
plate;
a front housing closing said front axial end of said cylinder block
via said front valve plate, and defining therein a front suction
chamber for refrigerant gas before compression and a front
discharge chamber for said refrigerant gas after compression;
a rear housing closing said rear axial end of said cylinder block
via said rear valve plate, and defining therein a rear suction
chamber for refrigerant gas before compression and a rear discharge
chamber for said refrigerant gas after compression;
a front suction valve stop means at end portions of said respective
cylinder bores and in said front axial end of said cylinder block
engaged by free ends of said respective front suction reed valves
during continuous operation of said front suction valve
element;
a rear suction valve stop means end portions of said respective
cylinder bores and in said rear axial end of said cylinder block
engaged by free ends of said respective rear suction reed valves
during continuous operation of said rear suction valve element;
said front suction valve stop means comprising:
a first predetermined engaging face having a first predetermined
depth with respect to said front axial end of said cylinder block
and being engaged by a frontmost portion of said free end of each
front suction reed valve to thereby provide each said front suction
reed valve with a preliminary step of stopping condition; and,
a second predetermined engaging face having a second predetermined
depth larger than that of said first predetermined engaging face
with respect to said front axial end of said cylinder block, said
second predetermined engaging face being engaged with said free end
of each said front suction reed valve at a portion contiguous to
said frontmost portion thereof to thereby provide said each front
suction reed valve with a final step of stopping condition; and
said rear suction valve stop means comprising:
a first predetermined engaging face having a first predetermined
depth with respect to said rear axial end of said cylinder block
and being engaged by a frontmost portion of said free end of each
rear suction reed valve to thereby provide each said rear suction
reed valve with a preliminary step of stopping condition; and,
a second predetermined engaging face having a second predetermined
depth larger than that of said first predetermined engaging face
with respect to said rear axial end of said cylinder block, said
second predetermined engaging face being engaged with said free end
of each said rear suction reed valve at a portion contiguous to
said frontmost portion thereof to thereby provide each said rear
suction reed valve with a final step of stopping condition.
Description
BACKGROUND OF THE INVENTION
1. Field of The Invention
The present invention relates to a piston type compressor with a
vibration-reducing suction valve mechanism, adapted for use as a
refrigerant compressing unit to be incorporated in a refrigerating
system or a climate control system. The refrigerating or climate
control system may be used in an automobile.
2. Description of the Invention
Generally, a piston type compressor, such as a swash plate type
compressor or a wobble plate type compressor, is provided with a
cylinder block having therein a plurality of cylinder bores defined
as compression chambers in which a plurality of pistons are
reciprocated to compress a refrigerant gas. The piston type
compressor further includes a valve plate or plates in which
suction and discharge ports are bored to be in registration with
the respective cylinder bores, suction and discharge reed valves
arranged in contact with the surfaces of the valve plate to
openably close the suction and discharge ports, and a housing or
housings to close the axial end or ends of the cylinder block via
the valve plate. The housing is arranged so as to define therein a
suction chamber for a refrigerant gas before compression and a
discharge chamber for the refrigerant gas after compression. The
suction and discharge reed valves are brought into a close contact
with the faces of the valve plate or valve plates when the
respective valves close the suction and discharge ports, and are
separated from the faces of the valve plate or plates when the
respective valves open the suction and discharge ports. Further,
the cylinder block is provided with stops arranged at end portions
of the respective cylinder bores so that the free ends of the
suction reed valves are engaged with and stopped by the stops when
the respective suction reed valves move from the position closing
the suction ports to the position opening the suction ports of the
valve plate or plates. Namely, the amount of opening of the
respective suction reed valves is restricted by the stops of the
cylinder blocks, and the stops are usually formed in recesses
provided by cutting a part of the end portion of a cylindrical wall
enclosing each cylinder bore. Thus, the opening amount of each
suction reed valve is determined by a depth of each recess formed
in the cylindrical wall of each cylinder bore. Nevertheless, when
the compressor operates at either an idling speed or a low rotating
speed, and at a small delivery capacity, the flow of refrigerant
gas throughout the refrigerating system including the compressor is
sharply reduced. Thus, the amount of refrigerant gas from the
suction chamber into the respective cylinder bores is very small,
and accordingly, the free end portion of each suction reed valve
cannot be sufficiently bent until the free end portion of the
suction reed valve is certainly engaged with the recessed stop of
the cylinder block. Consequently, the suction reed valves cause
uncontrolled self-vibrating motions which generate noise.
On the other hand, when the depth of the respective recessed stops
is set small, although the self-vibrating problem of the suction
reed valves can be overcome, the amount of opening of the suction
reed valves is necessarily made small. Accordingly, suction
performance of the suction valve mechanism of the piston type
compressor must be reduced.
SUMMARY OF THE INVENTION
Therefore, a primary object of the present invention is to prevent
not only a reduction in the suction performance of the suction reed
valves of the suction valve mechanism of a piston type compressor
but also an occurrence of self-vibration of the suction reed valves
of the compressor.
Another object of the present invention is to provide a piston type
compressor provided with a suction valve mechanism having a simple
stop unit for stopping the suction reed valves at an optimum
opening position thereof without causing self-vibration and noise
of the suction reed valves over an entire range of a rotating speed
of the compressor and a reduction in the suction performance of the
suction valve mechanism.
In accordance with the present invention, there is provided a
piston type refrigerant compressor which comprises
a cylinder block provided with a plurality of cylinder bores
circumferentially arranged around a central axis thereof, the
cylinder bores receiving a plurality of reciprocating pistons.
At least one valve plate is arranged adjacent to an axial end of
the cylinder block, and is provided with a plurality of pairs of
suction and discharge ports bored therethrough at positions in
registration with the respective cylinder bores.
A suction valve element is arranged adjacent to one face of the
valve plate, and includes a plurality of suction reed valves for
openably closing the suction ports of the valve plate.
A discharge valve element is arranged adjacent to the other face of
the valve plate and arranged for openably closing the discharge
ports of the valve plate.
At least one housing is arranged for closing the axial end of the
cylinder block via the valve plate, and defining therein a suction
chamber for refrigerant gas before compression and a discharge
chamber for the refrigerant gas after compression.
A suction valve stop means is arranged at end portions of the
respective cylinder bores to be engaged by free ends of the
respective suction reed valves during continuous operation of the
suction valve element.
An arrangement wherein the suction valve stop means comprises
a first predetermined engaging face having a first predetermined
depth with respect to the axial end of the cylinder block and being
engaged by a frontmost portion of the free end of each suction reed
valve to thereby provide each suction reed valve with a preliminary
step of stopping motion.
A second predetermined engaging face having a second predetermined
depth larger than the first predetermined engaging face with
respect to the axial end of the cylinder block is also provided,
the second predetermined engaging face being engaged with the free
end of each suction reed valve at a portion contiguous to the
frontmost portion thereof to thereby provide each suction reed
valve with a final step of stopping motion.
Preferably, the first and second predetermined engaging faces of
the suction valve stopping means comprise a first and second
partial counter-bores formed in the end portions of the respective
cylinder bores, the first and second partial counter-bores being
enclosed by a first and second partial cylindrical walls,
respectively.
Preferably, the first and second partial cylindrical walls of the
suction valve stopping means extend to have an equal radius of
curvature.
In the suction valve stopping means according to the present
invention, when the suction reed valves of the suction valve
mechanism move from the closing positions thereof closing the
associated suction ports to the opening positions thereof in
response to a suction stroke of the respective pistons, the
frontmost portion of the free end of each suction reed valve bends
and comes into engagement with the first predetermined engaging
face of the suction valve stop means to be subjected to the first
preliminary stopping motion whereby the suction reed valves are
prevented from causing uncontrolled self-vibration. Subsequently,
each suction reed valve further bends until the portion contiguous
to the frontmost portion thereof comes into engagement with the
second predetermined engaging face to be subjected to the final
step of stopping motion. Thus, the opening motion of each suction
reed valve of the suction valve mechanism is completed so as to
permit the associated cylinder bore to suck the refrigerant gas
before compression from the suction chamber.
It should be understood that since the first predetermined engaging
face of the suction valve stopping mechanism is arranged so as to
provide the frontmost portion of each of the suction reed valves
with the above-mentioned preliminary stopping motion irrespective
of operating condition of the piston type refrigerant compressor,
the suction valve mechanism of the compressor can be prevented from
causing the uncontrolled self-vibration of the suction reed valves
during all operating conditions of the compressor.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present
invention will be made apparent from the ensuing description of the
preferred embodiment thereof, with reference to the accompanying
drawings wherein:
FIG. 1 is a longitudinal cross-sectional view of a piston type
refrigerant compressor according to a preferred embodiment of the
present invention;
FIG. 2 is a front view of a suction valve element having a
plurality of suction reed valves;
FIG. 3 is an enlarged explanatory view of one of a plurality of
cylinder bores and an associated suction reed valve, illustrating a
positional and operational relationship therebetween;
FIG. 4 is a schematic cross-sectional view of an end portion of one
of the cylinder bores and a part of a valve plate, illustrating a
final opening motion of one of the suction reed valves of the
suction valve element of FIG. 2; and,
FIG. 5 is a similar schematic cross-sectional view of an end
portion of one of the cylinder bores and a part of a valve plate,
illustrating a preliminary opening motion of one of the suction
reed valves of the suction valve element of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, a piston type compressor is provided with a
cylinder block CB including a front cylinder block 1 having a
plurality of (five) cylinder bores 11, and a rear cylinder block 2
having a plurality of (five) cylinder bores 11 coaxial with the
cylinder bores 11 of the front cylinder block 1. The cylinder block
CB has axial ends closed by a front housing 5 via a front valve
plate 3, and by a rear housing 6 via a rear valve plate 4. The
front housing 5, the front valve plate 3, the front cylinder block
1, the rear cylinder block 2, the rear valve plate 4, the rear
housing 6 are tightly secured together by a plurality of long screw
bolts 7 which are inserted in axial screw bores 1a and 2a. The
cylinder block CB including the front and rear cylinder blocks 1
and 2 is provided with a swash plate chamber 8 arranged in a
connecting portion of the front and rear cylinder blocks 1 and 2.
The swash plate chamber 8 receives therein a swash plate 10 fixedly
mounted on a drive shaft 9 arranged so as to extend in coaxial
central bores 1b and 2b. The front and rear cylinder blocks 1 and 2
have five cylinder bores 11, respectively, extending axially
coaxially. The cylinder bores 11 are circumferentially arranged
around the central axis of the cylinder block CB, and slidably
receive therein double-headed pistons 12 which are operatively
engaged with the swash plate 10 via semi-spherical shoes 13.
The front and rear housings 5 and 6 are internally provided with
front and rear suction chambers 14 and 15, and front and rear
discharge chambers 16 and 17. The front suction and discharge
chambers 14 and 16, and the rear suction and discharge chambers 15
and 17 are fluidly isolated by front and rear partition walls 30
and 31, respectively. The front and rear valve plates 3 and 4 are
provided with a plurality of suction ports 18 and 19 formed
therein, respectively, for introducing refrigerant gas before
compression (low pressure gas) from the front and rear suction
chambers 14 and 15 into the respective cylinder bores 11 in
response to the suction stroke of the double-headed pistons 12. The
front and rear valve plates 3 and 4 are also provided with a
plurality of discharge ports 20 and 21 formed therein,
respectively, for discharging the refrigerant gas after compression
(high pressure gas) from the respective cylinder bores 11 into the
front and rear discharge chambers 16 and 17.
The front and rear valve plates 3 and 4 are further provided with
front and rear suction valve elements 22 and 23 attached to inner
faces thereof, i.e., the faces confronting the axial ends of the
front and rear cylinder blocks 1 and 2. The front and rear valve
plates 3 and 4 are also provided with front and rear discharge
valve elements 24 and 25 attached to outer faces thereof, i.e., the
faces confronting the front and rear housings 5 and 6, via front
and rear valve retainers 24a and 25a.
The rear cylinder block 2 is provided with a mount 26 at an upper
portion thereof so as to be capable of being connected to a
non-illustrated flange member by which the compressor is connected
to an external refrigerating system. The mount 26 is provided with
an inlet port (not shown in FIG. 1) having an end opening into the
swash plate chamber 8, so that the refrigerant gas before
compression is introduced from the external refrigerating system
into the swash plate chamber 8 via the inlet port. The front and
rear cylinder blocks 1 and 2 are also provided with a plurality of
inlet passageways 28 and 29 formed in a central portion thereof
adjacent to the central bores 1b and 2b, and located between two
respective cylinder bores 11. The inlet passageways 28 and 29 are
provided for permitting the refrigerant gas to flow from the swash
plate chamber 8 into the respective suction chambers 14 and 15.
The above-mentioned mount 26 is further provided with an outlet
port (not shown) which is fluidly communicated with discharge
passageways (not shown) formed in the front and rear cylinder
blocks 1 and 2 and located between two respective cylinder bores
11. The discharge passageways communicate with the front and rear
discharge chambers 16 and 17, so that the refrigerant gas after
compression is delivered from the discharge chambers 16 and 17
toward the external refrigerating system via the discharge
passageways and the above-mentioned outlet port.
A description of a suction valve mechanism incorporated in the
above-described compressor will be provided below.
The suction valve mechanism is provided with the above-mentioned
front and rear suction valve elements 22, 23, the front and rear
suction ports 18, 19, and a later-described suction reed valve
stopping means arranged on each of the front and rear sides of the
compressor to control the opening motion of later-described suction
reed valves of the front and rear suction valve elements 22 and 23.
At this stage, since the suction reed valve stopping means on the
front side is similar to that on the rear side, the description of
the suction reed valve stopping means arranged on the rear side of
the compressor is typically provided below with reference to FIGS.
2 through 5.
Referring to FIG. 2, the rear suction valve element 23 is formed as
a single disk-like element provided with a plurality of (five)
suction reed valves 23a arranged so as to confront the
corresponding number of (five) cylinder bores 11 of the rear
cylinder block 2 (see FIG. 1). The suction reed valves 23a are
formed as independent flexible reeds arranged so as to be radially
inwardly directed from the circumference of the disk-shape rear
suction valve element 23 to the center of the same element 23. Each
of the reed valves 23a has a free front end and a base portion
adjacent to the circumference of the valve element 23.
As shown in FIGS. 3 through 5, each reed valve 23a extends
diametrically with respect to the related cylinder bore 11, and the
above-mentioned free front end of the reed valve 23a extends beyond
the circular edge of the cylinder bore 11 (see FIG. 3).
The cylinder bore 11 is provided with a valve engaging portion 40
which acts as a valve stop for limiting an opening of the suction
reed valve 23a. The valve engaging portion 40 consists of a recess
formed by cutting a part of the inner wall of the cylindrical bore
11 at a position corresponding to the axial end of the cylinder
bore 11 and in registration with the free end portion of the
suction reed valve 23a.
The valve engaging portion 40 includes a first engaging face
portion 41 formed so as to be engaged by the frontmost end portion
of the flexible suction reed valve 23a during the initial stage of
the opening motion of the suction reed valve 23a, and a second
engaging face portion 42 formed so as to be engaged by a radially
inner portion of the suction reed valve 23a, which portion is
contiguous with the frontmost end portion thereof, during the final
stage of the opening motion of the suction reed valve 23a. Namely,
the first engaging face portion 41 of the engaging portion 40 can
provide the suction reed valve 23a with a preliminary step of
stopping upon being engaged by the frontmost end portion of the
suction reed valve 23a, and the second engaging face portion 42 of
the valve engaging portion 40 formed so as to have an axial depth
from the axial end of the cylinder bore 11 which is deeper than
that of the first engaging face portion 41 can provide the suction
reed valve 23a with a final step of stopping upon being engaged by
the above-mentioned radially inner portion of the suction reed
valve. When the suction reed valve 23a is finally stopped by the
engagement of the radially inner portion thereof with the second
engaging face portion 42 of the engaging portion 40, the opening
motion of the suction reed valve 23a due to flexing thereof is
compulsorily stopped.
It should be noted that the first and second engaging face portions
41 and 42 of the valve engaging portion 40 are formed as
counter-bores having partial circular walls 41a and 42a,
respectively, as best shown in FIG. 3.
As clearly shown in FIG. 4, the first engaging face portion 41 of
the valve engaging portion 40 has an axial depth "H.sub.1 "
measured at an edge of the cylinder bore 11 from the axial end
thereof, and the depth H.sub.1 is predetermined so that when the
suction reed valve 23a of the rear suction valve element 23 is
opened and flexed by a suction pressure acting from the cylinder
bore 11, the frontmost end portion of the suction reed valve 23a is
engaged with and stopped by the first engaging face portion 41,
without fail, irrespective of any change in the operating condition
of the compressor. Namely, as shown in FIG. 5, the suction reed
valves 23a of the rear suction valve element 23 are always given
the preliminary step of stopping due to the engagement of the
frontmost end portion thereof with the first engaging face portion
41.
The second engaging end face portion 42 of the valve engaging
portion 40 of the cylinder bore 11 has an axial depth "H.sub.2 "
measured at an edge of the cylinder bore 11 from the axial end of
the cylinder bore 11.
As shown in FIG. 4, the depth "H.sub.2 " is deeper than the depth
"H.sub.1 ", and is predetermined so that when the suction reed
valve 23a of the rear suction valve element 23 is further opened
and flexed after the engagement of the frontmost end portion
thereof with the first engaging face portion 41, the radially inner
portion contiguous with the frontmost end portion of the suction
reed valve 23a can be engaged with and stopped by the second
engaging face portion 42 of the valve engaging portion 40 of the
cylinder bore 11, and thus an optimum amount of opening of the
suction reed valve 23a is stably obtained so as to permit the
refrigerant gas to flow into the cylinder bore 11 from the rear
suction chamber 15 via the rear suction port 19. The first and
second engaging face portions 41 and 42 are not shown in FIG. 1, in
view of the limited space in FIG. 1.
It should be understood that the front suction valve mechanism
arranged on the front side of the compressor has a similar
construction and a similar operation to the above-mentioned rear
suction valve mechanism arranged on the rear side of the
compressor.
In the piston type compressor provided with the above-described
suction valve mechanism on each of the front and rear sides of the
compressor, when the drive shaft 9 is rotated together with the
swash plate 10, the respective double-headed pistons 12 are
reciprocated in the respective cylinder bores 11 so as to perform
suction of the refrigerant gas, compression of the refrigerant gas,
and discharge of the compressed refrigerant gas in cooperation with
the cylinder bores 11 of the cylinder block CB. When the
refrigerant gas before compression is introduced into the swash
plate chamber 8 from the external refrigerating system, via the
inlet port of the mount 26, and when the refrigerant gas flows from
the swash plate chamber 8 into e.g., the rear suction chamber 15
via the inlet passageway 29, the refrigerant gas is sucked into the
respective cylinder bores 11 in response to the suction stroke of
the respective pistons 12 via the suction ports 19 and the opened
suction reed valves 23a of the rear suction valve element 23.
Subsequently, the sucked refrigerant gas is gradually compressed by
the respective pistons 12 during the compression stroke thereof
within the cylinder bores 11, and the compressed refrigerant gas is
discharged from the respective cylinder bores 11 into the rear
discharge chamber 17 when the pressure of the refrigerant gas
reaches a predetermined pressure value sufficient for opening the
discharge valve element 25, via the rear discharge port 21.
During the suction stroke of the respective pistons 12 in the
cylinder bores 11, when pressure in the respective cylinder bores
11 is reduced to a level lower than that of pressure prevailing in
the rear suction chamber 15, the respective suction reed valves 23a
of the rear suction valve element 23 start to flex and open the
suction ports 19. At the initial flexing stage, the suction reed
valves 23a engage, at the frontmost end portions thereof, with the
first engaging face portions 41 of the respective cylinder bores 11
so as to be brought into a preliminary step of a stopping condition
thereof by the engagement with the first engaging face portions 41,
as shown by solid lines in FIG. 5. Thus, any uncontrolled
self-vibrating motion of the respective suction reed valves 23a of
the rear suction valve element 23 is suppressed. Subsequently, when
the suction reed valves 23a are further flexed to have a deeply
bent posture thereof as shown in FIG. 4, the radially inner
portions of the suction reed valves 23a are engaged with edges of
the respective second engaging face portions 42, and thus, the
suction reed valves 23a of the rear suction valve element 23 are
brought into the final step of a stopping condition where an
optimum amount of opening area for permitting an introduction of
the refrigerant gas before compression into the cylinder bores 11
via the suction ports 19 is stably established between the rear
suction ports 19 and the respective cylinder bores 11.
When the compressor is running at a relatively small delivery
capacity operation, the final step of a stopping condition of the
suction reed valves 23a of the rear suction valve element 23 is
reduced to a state shown by two dotted broken lines in FIG. 5.
However, the frontmost portions of the respective suction reed
valves 23a of the suction valve element 23 can be always engaged
with and stopped by the first engaging face portions 41 so that
occurrence of self-vibration of the suction reed valves 23a of the
rear suction valve element 23 can be certainly prevented, and
accordingly, noise is not generated.
In the described embodiment of the present invention, the first and
second engaging face portions 41 and 42 of the valve engaging
portions 40 of the suction reed valve stopping means are formed as
counter-bores having partial circular walls 41a and 42a as shown in
FIG. 3. Therefore, it will be understood that the portions 41 and
42 of the valve engaging portions 40 can be easily bored by using a
conventional cutting tool, i.e., a conventional end mill. At this
stage, if the side walls 41a and 42a of the first and second
engaging face portions 41 and 42 are given an equal radius of
curvature, the two portions 41 and 42 can be bored by the same end
mill without changing a cutting tool. Thus, simple production of
the valve engaging portions of the suction valve stopping means can
be achieved.
From the foregoing description of the preferred embodiment of the
present invention, it will be understood that the front and rear
suction valve mechanisms incorporated in a piston type compressor
are provided with suction valve stopping means for limiting the
opening motion of the suction reed valves of the front and rear
suction valve element in two steps, i.e., the preliminary step of a
stopping condition in which the frontmost end portions of the
respective suction reed valves can be constantly stopped so as to
prevent occurrence of uncontrolled self-vibration of the suction
reed valves, and the final step of a stopping condition in which an
optimum mount of suction opening permitting the refrigerant gas
before compression to be certainly introduced into the respective
cylinder bores from the suction chambers via the suction ports of
the valve plates can be stably established. Thus, the operation of
the compressor can be quiet due to prevention of any noisy sound
caused by the self-vibration of the suction valve elements.
Further, the valve engaging portions of the respective cylinder
bores can be easily manufactured by using a conventional cutting
tool. Thus, productivity of the front and rear suction valve
mechanisms of the piston type compressor can be increased.
Moreover, since the valve engaging portions of the suction valve
stopping means are formed by the cylindrical counter-bores provided
in the axial end of the cylinder block, it is possible to provide
such valve engaging portions of the suction valve stopping means by
effectively using small portions of the axial end or ends of the
cylinder block around the respective cylinder bores. Namely, an
existing portion of the interior of the compressor can
advantageously used for constructing the suction valve mechanism of
the piston type compressor without employment of any additional
part or element.
It should be understood that many modifications and variations will
occur to persons skilled in the art without departing from the
spirit and scope of the invention claimed in the accompanying
claims.
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